Understanding of SARS-CoV-2 pathogenicity in COVID-19 cynomolgus macaque model and consideration of its reinfection

Abstract

Abstract Although rapid vaccination has been progressing in the world as a countermeasure against COVID-19, the pandemic of SARS-CoV-2 is still raging worldwide due to the continuous emergence of several variants. We have established the COVID-19 cynomolgus macaque (CM) model using healthy young CMs and advanced-age CMs and the differences observed between the pathologies of young and elderly macaques were similar that those seen in humans. In the present study, we analyzed viral dynamics and pathology of SARS-CoV-2 variants of concern (VOCs) from Wuhan to Omicrons using the COVID-19 CM model. Delta infection displayed a greater virulence and Omicron infection showed a lesser virulence. Elucidation of how adaptive immunity in patients is induced by SARS-CoV-2 natural infection is critical for establishing a vaccine strategy, serologic therapies, public health control and prediction of infection. Therefore, we conducted the prolonged rechallenge analysis using the COVID-19 CM model reinoculated with either the same or a different strain of SARS-CoV-2 that was used for the initial infection. Re-infection was confirmed between different virus strains and PCR re-positivity was also observed between same VOC strain in some cases. Anti-RBD antibodies against Wuhan, Alpha, and Delta, were well induced by each VOC infection, but not against Omicrons. Antigen-specific cellular responses are also currently being analyzed. Overall, studies using COVID-19 CM models should contribute to the elucidation of the complicated pathophysiology of COVID-19. In addition, COVID-19 CM model should be useful for understand the virus evolution and to consider vaccine strategy to overcome the COVID-19 pandemic. AMED JP21fk0108414 AMED JP223fa727002 JSPS 21K19395